Roller with spray-coated surface structure

ABSTRACT

A roller has a spray-coated surface structure that provides the roller with an increased surface friction, so that the roller is suitable for push feeding sheet material. The spray-coated surface structure includes a coarsened layer, a finished layer, and a frictional layer provided on an outer circumferential surface of the roller from inner to outer side. The frictional layer is formed by mixing predetermined amount of liquid polyester with predetermined amount of silicon carbide powder and/or alumina oxide powder at normal temperature and pressure, evenly spraying the mixture over the roller, heating the roller for the mixture to set on the outer surface of the roller, and allowing the roller to cool.

FIELD OF THE INVENTION

The present invention relates to a roller with spray-coated surface structure, and more particularly to a roller that is subjected to a predetermined surface finishing and heating, and is then evenly sprayed with a mixture of liquid polyester and powder to obtain an increased surface friction.

BACKGROUND OF THE INVENTION

A roller is an important element frequently used in different machines to push feed sheet material. For example, a roller is frequently used in a printer, a photocopier, and many other office machines to roll on a top of a stack of sheet paper, so as to push and feed the sheet paper at the highest position of the stack.

Most of the conventional rollers are produced to have a smooth outer circumferential surface that provides insufficient frictional force in push feeding the sheet material and results in idling of the roller. One of the conventional ways to solve this problem is to form patterns on the roller by engraving the outer circumferential surface of the roller. This solution is highly labor and time consuming, particularly for a metal roller.

Another conventional solution is to put a soft rubber sleeve over the circumferential surface of the roller, in order to increase the frictional force of the roller. However, the putting of the rubber sleeve over the roller increases not only the manufacturing cost but also the manufacturing process of the roller. Moreover, the rubber sleeve has low thermal plasticity and durability, and tends to become worn out or hardened after being used over a prolonged time, preventing the roller from stably push feeding the sheet material.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a roller with spray-coated surface structure, in which liquid polyester is used as a medium to achieve an even and stable coating of a mixture of polyester and powder over the roller through simple and quick procedures.

Another object of the present invention is to provide a roller with spray-coated surface structure that can be achieved without consuming too much energy.

To achieve the above and other objects, the roller with spray-coated surface structure according to the present invention includes a coarsened layer, a finished layer, and a frictional layer provided on an outer circumferential surface of the roller from inner to outer side. The frictional layer is formed by mixing predetermined amount of liquid polyester with predetermined amount of silicon carbide powder or alumina oxide powder at normal temperature and pressure, evenly spraying the mixture over the heated roller, heating the roller again for the mixture to set on the outer surface of the roller, and allowing the roller to cool.

The roller with spray-coated surface structure so produced has increased surface friction and wear-resistance, and is therefore very suitable for push feeding sheet material.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is a fragmentary perspective view of a roller with spray-coated surface structure according to the present invention; and

FIG. 2 is a cross-sectional view of the roller of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2 that are perspective and cross-sectional views, respectively, of a roller with spray-coated surface structure according to the present invention. As shown, the roller is made of a metal material and generally denoted with a reference numeral 11. An outer circumferential surface of the metal roller 11 is subjected to coarsening, so as to form a coarsened layer 12. An outer circumferential surface of the coarsened layer 12 is subjected to a predetermined surface finishing, such as metal plating, metal spraying, etc., so as to form a finished layer 13 to increase the life, the wear-resistance, and the smoothness of the roller 11. A frictional layer 14 is further formed over the finished layer 13 to largely increase the surface friction of the roller 11, so that the roller 11 is suitable for use as a feeding roller in a printer, a photocopier, etc. to push feed sheets of paper.

The frictional layer 14 is formed by way of heating the roller 11 to a temperature between 70° C. and 80° C., and using a spray nozzle to evenly spray a mixture of polyester (PE) and one or more predetermined types of powder, such as silicon carbide powder and alumina oxide powder, on the outer circumferential surface of the roller 11. The sprayed mixture on the roller 11 has a thickness between 40μ and 100μ. Thereafter, the roller 11 with the sprayed mixture of PE and powder is heated to 180° C., so that the mixture is set on the finished layer 13. When the roller 11 is cooled, the PE functions for the silicon carbide powder and/or the alumina oxide powder to evenly and firmly attach to the surface of the roller 11 to largely increase the surface friction thereof.

The above-mentioned mixture is prepared by stirring to mix 60-70 wt % of liquid polyester with 30-40 wt % of silicon carbide powder and/or alumina oxide powder at normal temperature and pressure. The prepared mixture is then guided into a spray nozzle (not shown) for subsequent spray coating.

The mixture may include only one of the silicon carbide powder and the alumina oxide powder, or a combination thereof.

Since the liquid polyester and the powder are stirred and mixed at normal temperature and pressure, energy consumed in preparing the mixture is low. Therefore, the roller with spray-coated surface structure according to the present invention can be more easily and quickly produced at much more reduced cost as compared to the conventional technique, in which a metal roller is engraved on an outer surface to produce patterns.

The present invention has been described with a metal roller. However, it is apparent the present invention may be applied to rollers made of other materials, such as a plastic roller, with which polyester may be associated without being heated first, enabling the prepared mixture to be directly sprayed over the surface of the plastic roller. Thus, this and many other changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. A roller with spray-coated surface structure, comprising a metal roller having a coarsened layer, a finished layer, and a frictional layer sequentially formed on an outer circumferential surface of said metal roller from inner to outer side; said coarsened layer being formed by coarsening an outer circumferential surface of said metal roller; said finished layer being formed by subjecting an outer circumferential surface of said coarsened layer to a predetermined surface finishing; and said frictional layer being formed by heating said metal roller to a temperature between 70° C. and 80° C., using a spray nozzle to evenly spray a mixture of polyester and at least one type of powder over the outer circumferential surface of said finished layer of said metal roller, so that the sprayed mixture on said metal roller has a thickness between 40μ and 100μ; heating said metal roller coated with the sprayed mixture of polyester and powder to 180° C. for the mixture to set on said finished layer; and allowing said metal roller to cool.
 2. The roller with spray-coated surface structure as claimed in claim 1, wherein said mixture is prepared by stirring to mix 60-70 wt % of liquid polyester with 30-40 wt % of silicon carbide powder and/or alumina oxide powder at normal temperature and pressure.
 3. The roller with spray-coated surface structure as claimed in claim 1, wherein said surface finishing is metal plating, and said finished layer is a plated metal layer. 